Technical Summary
This document updates the existing RIPv2 cryptographic authentication
mechanism specification (RFC 2082) to add support for the SHA-1 family
of hash algorithms using the widely accepted HMAC approach, while
retaining the existing use of Keyed MD5 for backwards compatibility.
This enhancement provides a broader range of cryptographic choice to
operators, while retaining backwards compatibility with the existing
specification.
The SHA-1 family of algorithms is generally considered to be stronger
and have a longer useful future operational life than MD5. The HMAC
approach is now widely accepted by the IETF and so is used for the new
algorithms, while retaining the historic "Keyed Hash" approach for the
existing MD5 algorithm in order to retain backwards compatibility and
interoperability with existing implementations. The SHA-1 family of
algorithms happens to be a US Federal Information Processing
Publication (which are developed by NIST), but the family of
algorithms are broadly accepted globally, with several different
countries having a formal preference for that family of hash functions
over other hash functions.
Once approved, this document will replace RFC 2082.
Working Group Summary
This is an individual submission. It is not the product of any
working group, and it has not been reviewed by any IETF working group.
The document was is co-authored by someone at NIST, and it was also
reviewed by several other people at NIST. The other author is one of
the original authors of this mechanism (from RFC 2082). The
desirability of undertaking this enhancement was discussed several
months ago on the IETF Security Area Advisory Group (SAAG) mailing
list.
Protocol Quality
The original specification in RFC 2082 is very widely implemented and
has demonstrated broad interoperability among a number of router
vendors. It is also available in at least one freely available RIPv2
implementation for UNIX.
The new specification has not yet been implemented. However, the new
protocol varies from the previous version only in the addition of
support for additional cryptographic algorithms. Thus, no
implementation issues are expected.
This document was reviewed by Russ Housley for the IESG.
IESG Note
In the interests of encouraging rapid migration away from
Keyed-MD5 and its known weakness, the IESG has approved this
document even though it does not meet the guidelines in BCP 107
(RFC 4107). However, the IESG stresses that automated key
management should be used to establish session keys and urges
that the future work on key management described in Section 5.6
of this document should be performed as soon as possible.